1. Field of the Invention
The invention relates generally to spring-loaded, pushbutton pin couplers and particularly to a locking structure formed with a button latch pin of such couplers for preventing inadvertent uncoupling through accidental depression of the button latch pin.
2. Description of the Prior Art
Pushbutton pin couplers or connectors have long been used for coupling structural elements together, such elements commonly comprising collapsible or extendible arms or legs. Such couplers comprise a spring-loaded "button latch" pin mounted within a first structural element which is to be coupled to a second structural element. The first structural element has an aperture formed therein through which the button latch pin extends by virtue of force exerted by a spring mounted within a housing interiorly of the first structural element, the housing mounting the button latch pin for movement therewithin under the influence of said spring. The second structural element is provided with an aperture which mates the aperture of the first structural element, the button latch pin being depressible into the interior of the first structural element such that the aperture in the second structure can be aligned with the aperture in the first structural element. On alignment of the apertures, the pressure biasing the button latch pin inwardly of the first structural element is removed and the pin is biased outwardly by the spring, the pin thus extending through both apertures and acting to hold the two structural elements together. As can readily be seen from the foregoing description of the operation of a pushbutton pin coupler, a force directed against the button latch pin from externally of the coupled arrangement can cause the pin to be accidentally depressed and thus allow the coupled structural elements to disengage. In many coupling situations, such as the coupling of helical auger flight sections used in ice and frozen ground drilling, accidental decoupling of the pushbutton pin couplers holding the flight sections together results in the helical auger and associated flight sections below the uncoupled joint being left in the material being drilled. Accordingly, a long-felt need in the art has existed for providing means to prevent the accidental uncoupling of a pushbutton pin coupler.
In U.S. Pat. No. 4,597,472, Hjelm describes a spring-loaded latching pin which is locked into place by means of a second pin attached directly to the latching pin. Rotation of the latching pin in either an engaged or disengaged configuration allows the second pin to engage respective legs of a slot formed in the structure housing the latching pin. As such, Hjelm describes a pin coupler of sorts having structure capable of locking the pin coupler in a coupled configuration. In U.S. Pat. No. 3,449,003, Hunt provides two pins in a latch connection in an effort to ensure that the connection does not disengage. However, Hunt does not provide additional coupling structure which would prevent inadvertent depression of either of the latch pins included in the coupling. Specht, in U.S. Pat. No. 2,675,257, provides a button latch pin for connecting sections of a boring auger, the body of the auger carrying the latch pin also having a pin element extending transversely to the latch pin from the wall of the body and into engagement with the latch pin. However, this transversely extending pin only acts to limit the degree of travel of the latch pin and does not lock the latch pin in an engaged position. In U.S. Pat. No. 4,042,305, Vincent provides a button latch pin which operates in a conventional manner and is exemplary of a large body of art disclosing button latch pins which are not provided with structure capable of locking a button latch pin into a coupled configuration. Thomas, in U.S. Pat. No. 2,284,180, discloses a spring-loaded latching pin which is engaged or disengaged by manipulation of a pin disposed transversely to the latch pin and which is operated by a screwdriver to bias the latch pin out of engagement with structure which is being latched. While the structure of Thomas may act to prevent inadvertent disengagement of the spring-loaded pin element, neither Thomas nor any of the other references cited above provides a button latch pin having a restraining seat located at the anterior end of the pin and which cooperates with a second pin protruding transversely from a button latch pin housing within which the button latch pin is disposed, thereby enabling the button latch pin to be locked or released depending on the rotational position of the latch pin. The simple yet effective structure of the present invention is therefore an advance in the art due to the functioning of the present structure to prevent accidental uncoupling of a joint latched by a spring-loaded, pushbutton pin coupler.